New Zinc(II) Complexes with Tetradentate Amino Acid Derivatives: Structure Characterization, Solution Chemistry, and in vitro Insulinomimetic Activity
作者:Yutaka Yoshikawa、Kenji Kawabe、Makoto Tadokoro、Yuka Suzuki、Naohisa Yanagihara、Akihiro Nakayama、Hiromu Sakurai、Yoshitane Kojima
DOI:10.1246/bcsj.75.2423
日期:2002.11
Twelve new amino acid derivatives/Zn(II) complexes were prepared by the reactions of ZnSO4 and nine tetradentate ligands, Gly, Ala, Val, Leu, Ser and His derivatives and three pentadentate ligands, Asp and His derivatives. The X-ray structure analysis of [Zn3(N-pyridylmethyl-His)3(H2O)2](ClO4)3·2H2O revealed the formation of a trinuclear complex, in which three tetradentate ligands and two water molecules coordinate to three Zn(II), but the complex in an aqueous solution is present as a monomeric complex ion. Several Zn(II) complexes were found to have in vitro insulinomimetic activity which was estimated by the inhibition of free fatty acid release in isolated rat adipocytes treated with epinephrine. It was revealed that the insulinomimetic activities of Zn(II) complexes with the stability constants (log β) less than 11 were higher than that of VOSO4 and were comparable to that of ZnSO4 as positive controls except in the cases of two complexes with Gly derivatives, Zn(N,N-dipyridylmethyl-Gly)+ and Zn(N,N′-trimethylene-bis-Gly).
通过ZnSO4与九种四齿配体(甘氨酸、丙氨酸、缬氨酸、亮氨酸、丝氨酸和组氨酸衍生物)和三种五齿配体(天冬氨酸和组氨酸衍生物)的反应,合成了十二种新的氨基酸衍生物/Zn(II)配合物。X射线结构分析显示,[Zn3(N-吡啶甲基-组氨酸)3(H2O)2](ClO4)3·2H2O形成了一种三核配合物,其中三个四齿配体和两个水分子与三个Zn(II)配位,但在水溶液中该配合物以单体配合物离子的形式存在。有几种Zn(II)配合物表现出体外胰岛素样活性,通过评估在注射肾上腺素处理的分离大鼠脂肪细胞中对游离脂肪酸释放的抑制作用来估计其活性。结果显示,稳定性常数(log β)小于11的Zn(II)配合物的胰岛素样活性高于VOSO4,并可与作为阳性对照的ZnSO4相媲美,但在两种含甘氨酸衍生物的配合物Zn(N,N-二吡啶甲基-甘氨酸)+和Zn(N,N′-三甲撑-双甘氨酸)的情况下例外。